Means for treating granular material



Nov. 18, 1941. s. OLSEN MEANS FOR TREATING GRANULAR MATERIAL Filed Oct.31, 1940 Z-Sheets-Sheet l Nov. 18, 1941. s. OLSEN 2,263,099

MEANS FOR TREATING GRANULAR MATERIAL Filed Oct. 31, 1940 2 SheetsSheet 2I I I I I I I I I I I I 5 1 v Patented Nov. 18; 1941 UNITED STATE sPATENT OFFICE MEANS FOR TREATING GnANULAa MATERIAL 2 Claims.

This invention relates to improvementsin an apparatus for treatinggranular or flaky material such as ground mica to suppress dust, theprocess being characterized in that dust i efficiently sup-.

pressed and yet the treated product is not sticky or tacky.

Granular materials such as ground mica or the like have heretofore beentreated with oil for the purpose of suppressing dust. The treatment,however, has been inefficient in that much more oil has been added tothe mica than is necessary. Portions of the treated material in mostinstances have been sticky or tacky due to having received too much oiland other portions 'thereof have been left dry due to the non-unition ofthe granular mass carries too much oil which would cause stickiness, andall portions of the mass carry suflicient oil to efficiently suppressdust.. a

Briefly described, my invention comprises mixing oil and air in a moreor less violent fashion in order to create an oil fog or mist andcontinuously passing thegranular particles through an atmosphere of suchoil fog or mist.

Other objects and advantages of my invention will be apparent from theaccompanying drawings and following detailed description.

In the drawings,

Fig. 1 is a diagrammatic elevational view, partly in section, ofsuitable apparatus for carrying out my invention.

Fig. 2 is a fragmentary view of a slight modification of apparatus.

Fig. 3 is a similar view of another modification of apparatus.

Fig. 4 is a sectional view of the air-oil mixing device, taken on line4-4 of Fig. 1.

Fig. 5 is a detailed sectional view of a valve employed with themodification of my invention shown in Fig. 3.

Referring in detail to the drawings, I indicates a tank for containingoil which is adapted to be employed in my process. A pipe 2 connectsinto the upper portion of tank I and extends downwardly into theinterior of the tank. A filter 3 is mounted on the lower end of the pipe2 within the tank I and is adapted to filter the oil passed from thetank through the pipe'i. The opposite end of pipe 2 is connected to amotor driven pump 4, the pipe 2 serving as the intake for said pumpwhereby oil can be withdrawn from tank I. A pipe 5 is also connected topump 4 and comprises one side of a looped header, the opposite sidecomprising pipe 6 which connects into the upper portion of tank I.

The arrangement is such that the motor driven pump 4 withdraws oil fromtank I and circulates the same through the headers 5 and 8, the oilreturning to tank I through the pipe 8. In practice the motor drivenpump 4 and tank I may be located in the basement of the plant and theheaders 5 and 6 may run to the various points to which the oil is to bedelivered.

A branch pipe I connects into header 5, a hand operated valve 8 beinginterposed in pipe I. The opposite end of pipe I connects into acentrifugal pump 9 which is driven by motor III. The pipe 1 comprisesthe intake for the pump 9. A pipe II comprises the discharge for pump 9,said pipe being connected at its opposite end to a mixer I2.

It is to be understood, of course, that as many branch pipes as desiredmay be connected into the header system, depending upon the number oftreating units which are adapted to be employed.

Referring particularly to Fig. 4, a sectional view of the mixer I2 isshown. The mixer comprises a casing I3 through which a shaft I4 extends.The shaft I4, at one end connects with shaft l5 of motor I II and at theopposite end connects with the rotor shaft of the centrifugal pump 9. Arotor I6 is mounted upon shaft I4 within the casing I3, the rotor I6being cylindrical in shape. The interior space I 1 within the casing I3is provided with curvilinear surfaces, the curvature of the majorportion of the defining wall of the space I! being eccentric withrespect to cylinder IS. A pair of diametral slots I8 is provided incylinder IS, a blade I9 being slidably positioned in each of the slots.A coil spring 20 is positioned at the base of each of the slots andfunctions to urge the blades I9 in a radially outwardly direction.

The mixer I2 is provided with an air' inlet 2| in addition to the oilinlet 'pipe I I, and said mixer is also provided with a vapor dischargeopening 22. In operation, rotation of the cylinder I6 causes a vacuum tobe created in that portion of the space I] in which the oil outlet pipeis connected and into which the air inlet opening communicates.Consequently, upon rotation of the rotor I6, a mixture of air and oil isdischarged pipe 26 connects with the discharge 22 and is provided at itsopposite end with a spray head 21. A gauge 28 connects into pipe 26 andis adapted to measure the pressure of the vapor in said pipe. The 'oilemployed in my process is of the relatively non-volatile, non-dryingtype, having a relatively low viscosity. By appropri ately controllingthe proportion of oil and air fed to the mixer i2, by properlymanipulating the valves I and 24. a fog or mist of atomized particles ofoil may be discharged from the mixer and through the head 21.Consequently, in the vicinity of the head 21 an atmosphere of oil, fogor mist is established. It is through this atmosphere that the granularmaterial to be treated is passed as will be hereinafter more fullydescribed.

Although my invention is applicable to many types of granular materials,it is ideally adapted for use in conjunction with ground mica and,hence. my invention will be described in con- Junction with its use insuppressing dust on ground mica.

In the grinding of mica to produce granular particles or flakes whichare adaptable for use in the roofing industry, as fillers for paints, orfor purposes of heat insulation, the mlcaceous rock is ground andsubsequently screened to divide the ground bulk into various meshclassifications. A hopper 28 which is of substantially conical shape isprovided for each class of ground mica. A plurality of conduits 20deliver ground mica as at II from the screens to the hopper 20. Thehopper 2| is provided with an opening 22 at its lower constricted endwhereby the mica discharged into the hopper 28 may be passed toappropriate bins or base.

In carrying out my invention a secondary hopper 32 is secured to theupper closure 24 of the main hopper 28, the secondary hopper beingsubstantially conical in shape and being provided with a dischargeopening I! at its lower constricted end. The motor Ii) together withmixer i2 and pump 8 may be mounted on the closure 24 and the vapordischarge pipe 26 may pass through said closure, positioning the sprayhead 21 adjacent the discharge opening 25.

In operation, the mica passed through conduits 20 from the screens isfirst passed into the hopper 13 and discharges therefrom through theopening 35. In passing through the constricted opening the micaparticles are compelled to pass through the atmosphere of oil fog ormist produced in the vicinity of the opening 25 by the spray head 21.The particles or flakes of mica in thus passing through the oil fog,have a microscopically thin film of oil deposited upon their surfaces.but is not suiiiciently thick upon the mica particles to cause theparticles to adhere to each other. In addition, all of the micaparticles must pass through the tached discrete particles. Hence, thedesired film is deposited upon the surfaces of each of ,the particles.

In each of the conduits 20, a damper 24 may be positioned whereby therate of flow of mica 2| through the conduits can be controlled. In orderto properly coat the particles of mica the flow of the mica through theconduits I is correlated with the discharge of vapor from the head 21.As the flow of mica increases, of course, the flow of vapor mustincrease in proportion. As has been hereinbefore described by properlymanipulating valves 8 and 24, the density of the vapor, that is, theproportion of oil to air may be controlled.

Referring particularly to Fig. 2, a slight modification of my inventionis illustrated. In Fig. 2

atmosphere of oil fog and in doing. so they pass through said atmosphereas de-' the same reference numerals will be employed to designateidentical apparatus. described in coniunction with Fig. 1 and forpurposes of clar-' This film is sufllcient to suppress dust hopper 51ity additional reference numerals will be applied only to those portionsof the device which differ from the apparatus shown and described incon- Junction with Fig. i.

In this form of my invention, a valve interposed in pipe as which leadsfrom the pump 9 to the mixer i2. The valve 21, as will be hereinaftermore fully described in conjunction with Fig. 5 of the drawings. isprovided with a movable plunger 39 which, when moved outwardly, permitsan increase in the passage of oil from the pump 8 to the mixer l2 andwhich, when moved inwardly, decreases the rate of passage of oil fromthe pump 8 to the mixer i2. A link 40 connects the end of the plunger 34with the damper 84, the operation being such that when the damper 36 ismoved to increase the flow of mica through the conduit 30, the plunger29 is moved outwardly thus increasing the flow of oil from the pump 8 tothe mixer i2. Of course, in order to have the proper vapor density atthe spray head when the mica-oil relationship is changed, the valve 24must be appropriately ma. nipulated to increase or decrease, as the casemay be, the supply of air to the mixer i2.

In the form of my invention illustrated in Fig. 2, that is, thesemi-automatic operation of the mica-oil control, only one conduit isemployed and therefore the flow of oil is automatically regulated withthe flow of mica passing through said conduit which would be the totalamount of mica treated. Referring particularly to Fig. 3. asemi-automatic arrangement is illustrated wherein more than one conduitis employed in conjunction with a single spray head. In this form of myinvention a hopper 4i is employed having a relatively conical shape andhaving an upper closure 42. A support 42 is mounted upon the hopper 4iand carries a motor 44 which drives the rotor of a mixer 45 and a rotorof a pump 48, the mixer 46 and pump 48 being identical in structure withthe mixer l2 and pump 9, respectively, hereinabove described;

A filter chamber 41 is positioned above the mixer 45 and connects withthe mixer by means of pipe 48 in which valve 48 is interposed. Thefilter 41 is identical in construction with the filter 25 hereinbeforedescribed. A pipe 50 controlled by valve 5| connects into pump 48, pipe50 connecting at its opposite end into one of the headers i or 8. Thepipe 50 serves as an oil intake for the pump 46 and a pipe 82 functionsas the discharge for the pump. The pipe 52 connects into a valve"whereby the amount of oil passed from the pump 48 to the mixer 48 maybe controlled. A pipe 54 is connected to mixer 4| and functions as thevapor discharge pipe from said mixer, pipe 54 carrying at its oppositeend a spray head 55, similar to the spray head 21 hereinbeforedescribed.

A plurality of conduits l6 connect into the upper closure 42 of thehopper 4i. A secondary is secured to the lower face of the closure 42and is conical in structure, the secondary hopper being connected to arelatively which serves as a mosphere of oil fog or mist immediatelyadjacent this vicinity.

A door 59 is hinged, as at 60, to the mouth of the cylindrical member58. A lug 6| is carried upon the lower face of the door 59 and a link 62is pivotally secured to the lug Bl. A bracket 53 is carried upon theouter surface of the secondary hopper 51 and serves as a fulcrum, as at54, for a lever 55. One end of lever 65 is pivotally connected as at 55to link 62, the opposite end of the lever 65 carrying a head 61 which isprovided with a slot 68.

Referring particularly to Fig. 5, the valve 53 comprises a cylindricalpipe 59, upon one end of which a packing gland 10 is threadedlyconnected. Pipe 52 connects into an intermediate portion of the pipe 59.A plunger 1| is slidably positioned in pipe 69, the inner end of saidplunger being tapered as at 12. The outer end of the plunger projectsthrough the packing gland 10 and carries a pin 13 which passes throughslot 69. When the plunger 1| is moved inwardly, the tapered portion 12of said plunger decreases the area of communication between the pipe 52and pipe 69 and, hence, the passage of oil from pump 45 to mixer 45 isdecreased. When the plunger 1| is moved outwardly, the area ofcommunication between pipe 52 and pipe 69 is increased, and the amountof oil passing from pump 46 to mixer 45 is accordingly increased.

In operation, the mica particles are discharged through the conduits 55into the secondary hopper 51. In leaving the conical portion of saidhopper, said particles pass through the atmosphere of oil fogestablished in the vicinity of the head 55. The mica particles then dropto the upper surface of the door 59. In view of the fact that thepassage of particles into the secondary hopper is a continuousoperation, the door 59, due to the weight of particles, will be opened apredetermined degree. By means of the lever 55 and linkage 62 theplunger 1| will be moved to a predetermined position depending upon theangular position of the door 59. The

"angular position of the door 59, of course, is

dependent upon the rate at which the particles drop upon the uppersurface of the'door. In this manner the rate of passage of oil from thepump 46 to the mixer 45 can be automatically.

controlled and correlated with the rate of passage of the micaparticles. 01 course, the air intake valve 49 must be manipulated inorder to secure the proper vapor density whenever a material change inthe rate of feed of mica to the secondary hopper 51 occurs.

The cylindrical neck 58 is of sufficient length that the atmosphere ofoil fog is created above the mica particles which may accumulate on theupper surface of the door 59. Hence,-while the mica particles rest uponthe upper surface of the door and before they flow therefrom into themain hopper 41, no additional oil is applied to said particles. The onlyplace wherein sai Dar; ticles receive oil is during their passagethrough the atmosphere created in the immediate vicinity of the head 55.It can readily be seen that by this arrangement an automatic control isestablished where more than one conduit feeds mica into the secondaryhopper 51.

In treating ground mica in my process, the

efficiency of the process, that is the economical uniform coverage ofthe mica by the oil is strikingly apparent from the fact that as low asone gallon of oil per ton of ground mica can be used 5 and the dust canbe effectively laid. As a maximum, about three gallons of oil per ton ofground mica can be used effectively without causing undue adherence ofthe flakes to each other. The size of the mica flakes which can beefficiently treated ranges from 4 to 90 mesh.

The oil used may be of an asphaltic, naphthenic or parafline base,having a viscosity at 100 F., of between about 50 and 100 seconds.Preferably the viscosity is between 60 to 80 Saybolt Universal at 100 F.The gravity of the oil ranges between about 22 to 32 Baum gravity. Ofcourse, oils other than hydrocarbon oils may be used providing that theyare substantially nonvolatile and non-drying and conform generally tothe gravity and viscosity ranges hereinbefore set forth.

Although my invention has been described in conjunction with thetreating of ground mica, it is also applicable to other granularmaterials such as slate granules, saw dust or the like.

I claim as my invention:

1. An apparatus for treating granular material to suppress the dustcarried thereon which comprises in combination, a primary hopper toreceive granular material, a secondary hopper positioned within saidprimary hopper, means for passing granular material into said secondaryhopper, said secondary hopper being provided with a relativelyrestricted communicating opening into said primary hopper whereby saidgranular material passes from said secondary hopper to said primaryhopper, a mixer, means for feeding oil into said mixer, means forfeeding air into said mixer, means for agitating said oil and air fed tosaid mixer in a relatively violent fashion, to suspend finely dividedparticles of oil in the air, a discharge pipe for said mixer, saiddischarge pipe having a mouth adjacent said re stricted communicatingopening in said secondary hopper, whereby said mixed oil and air createsan oil fog atmosphere in the vicinity of said communicating openingthrough which said granular material passes.

2. An apparatus for treating granular material to suppress the dustcarried thereon which comprises in combination, a hopper for receivinggranular material, said hopper having a restricted discharge opening,means for flowing granular material into said hopper, a mixer remotelypositioned with respect to said hopper, means for feeding oil into saidmixer, means for feeding air into said mixer, means for agitating saidoil and air fed to said mixer in a relatively violent manner to suspendfinely divided particles of oil in the air, a discharge pipe for saidmixer, the mouth of said discharge pipe being positioned in said hopperadjacent the path of travel of said granular material through saiddischarge opening out of said hbpper, whereby said mixed oil and aircreates an oil fog atmosphereadjacent said discharge opening throughwhich said granular material passes, and means for automaticallycontrolling the passage of oil to the 'mixer inresponse to changes inpassage of granular material, through said hopper.

SIGURD OLSEN.

